1. Field of the Invention
This invention relates to the use of N-tert-butyl-2,6-toluenediamine as an antioxidant for the prevention of oxidation of organic materials.
2. Description of the Prior Art
Aromatic amines and N-alkylated aromatic amines have been long recognized as antioxidant materials for a variety of organic compositions such a rubber, plastics, fuel oil, lubricating oils, mineral oil, motor fuels and the like. The following patents are deemed representative of some of the prior art with respect to the use of aromatic amines as an antioxidant.
U.S. Pat. No. 2,645,674 discloses a method for producing a stabilized rubber adhesive composition by incorporating various amounts of aromatic diamine into the rubber as an antioxidant. Examples of aromatic amines include p-phenylenediamine; 1,5-naphthalenediamine; N-cyclohexyl-p-phenylenediamine and ortho-tolyl-.beta.-naphthylamine.
U.S. Pat. No. 3,230,257 discloses the preparation of nuclear and N-alkylated aromatic amines and the use of these aromatic amines is antioxidants in mineral oil, lubricating oils, etc. Aromatic amines which are suitable for alkylation include 2,4-dibutylaniline and ethylated p-toluidine. Phenylenediamines are suggested as candidate amines.
U.S. Pat. No. 3,923,892 discloses the manufacture of alkylated aromatic amines and suggests their use as antioxidant materials. Examples of aromatic amines include methyl bis(aniline) and p-phenylenediamines. Diisobutylaniline and 2,3,5,6-tetraethyl-1,4-diaminobenzene are also suggested.
U.S. Pat. Nos. 2,692,287 and 2,692,288 disclose the production of N-tert-alkylated aromatic amines and the use as antioxidants. Example 6 of the U.S. Pat. No. 2,692,287 patent shows the manufacture and use of N-tert-butyl-2,4-diaminotoluene as an antioxidant for lubricating oils.
U.S. Pat. No. 4,456,541 discloses the use of various aromatic diamines as antioxidant materials, and specifically alkylated derivatives of toluenediamine. Of these aromatic diamines, the diethylated derivatives of the 2,4 and 2,6-isomers of toluenediamine are shown as being particularly effective antioxidant materials.